Method of manufacturing an automatic dishwashing detergent product

ABSTRACT

The present invention provides a method of manufacturing an automatic dishwashing detergent product, said product being provided as a discrete dosage unit and comprising a continuous, non-aqueous gel phase, comprising manufacturing said gel phase by a method comprising free radical polymerisation of monomer(s) in a non-aqueous reaction mixture to form a polymeric builder; wherein said reaction mixture comprises: at least one non-ionic surfactant which is an optionally end-capped alcohol alkoxylate; and one or more monomers comprising acrylic acid and optionally one or more further α,β-ethylenically unsaturated acids, wherein no more than 0.1 wt % of the total amount of the monomer(s) are crosslinking monomer(s).

TECHNICAL FIELD

The present invention is in the field of automatic dishwashingdetergents. In particular, it relates to an automatic dishwashingdetergent product that is a discrete dosage unit, comprising acontinuous, non-aqueous gel phase. The gel phase is both attractive toconsumers and shows good builder performance, and may be suitable forincorporation in a water-soluble container.

BACKGROUND

Unit dose detergent products are convenient for consumers, since thereis no need for them to measure out the required volume of detergent eachtime. Various unit dose formats, including tablets, and containers madeof water-soluble material, are already known. Water-soluble containersare attractive since they avoid direct consumer contact with thedetergent contents which are potentially irritant, and can have a fasterdissolution profile than tablets (because the detergent contents do notneed to be compacted particles). Fast dissolution in the wash is oftenrequired to release active ingredients from dosage units to be consumedin a single dishwasher run, so that they can become effective as soon aspossible, for instance before they are deactivated by the hightemperatures of the wash. Containers are preferred for this reason, andalso since they are capable of incorporating many more types ofcomposition including liquid, gel and paste compositions, not just solidones. With multi-compartment containers, more than one type ofcomposition can be incorporated (e.g. one solid and one liquidcomposition), incompatible ingredients can be kept separate until use,compartments can be designed to release their respective contents atdifferent times in the wash, and/or greater opportunities for improvedaesthetics are provided.

In practice in the automatic dishwashing (“ADW”) field, the choice ofavailable sizes and shapes of unit dose products is limited by the sizeand shape of machine dispensers into which they are to be placed. Thereis also a general demand in the art for more concentrated products whichuse less packaging and/or confer better performance by including higheramounts of active ingredients. It would therefore be useful to have acompact ADW unit dose detergent composition containing a high level ofingredients contributing to the performance.

When dealing with containers made from water-soluble material, it isalso important to ensure this material does not dissolve or deteriorateprior to the intended usage point of the container. Adverse interactionsbetween the container material and the container contents during storagecan potentially lead to container deformation, loss of mechanicalstrength of the product and rendering it unattractive. For these reasonsit is helpful for the detergent formulation inside the container to havea low water content. When space is an issue, it is also important tominimise the levels of carriers not contributing to performance in thewash, such as water. Nevertheless, whilst aqueous compositions are to beavoided, the composition must still be capable of dissolution in thewash, and ideally not leave residues on the dishware.

One particularly important type of ingredient in the context ofdetergent performance is a builder. Builders soften water by removingfree cations from the water, thereby increasing the performance of otherdetergent ingredients which are adversely affected by those cations.Mostly, they react with calcium and/or magnesium ions to form complexesor precipitates. Historically, phosphates like STPP and KTPP have beenthe mainstay detergent builders, but there are increasing regulatoryrestrictions on the use of these ingredients worldwide.

Gel formats are visually very attractive to consumers, especiallytransparent gels. However, there is a conflict between the requirementsfor low water content, high builder content, and the gel not beingopaque. Many available builders are solid at room temperature and do notdissolve in sufficient quantities in the non-water solvents typicallyused to produce anhydrous gels. For example, phosphates like STPP andKTPP and non-phosphate builders like MGDA and GLDA may be in dissolvedform in an aqueous formulation, but may be in the form of dispersedparticles in a non-aqueous formulation; dispersed particles can scatterlight and render the formulation opaque.

Previously, if a unit dose detergent product was to contain a builderand a transparent fluid, this was usually achieved in the form of amulti-compartment container, carrying builder comprised in a solidcomposition and/or opaque fluid in one compartment, and a transparentfluid containing no builder in a separate compartment. However, thedrive for higher performance and greater concentration of activeingredients has forced the present inventors to look for ways toincorporate builder in the transparent fluid too. In addition, liquidsand low viscosity gels are liable to leak out of a container if thecontainer material becomes damaged, so it would be desirable in thiscontext for the transparent fluid to be a self-standing gel.

Certain types of polyacrylic acid (and salts thereof) can act as abuilder (c.f. U.S. Pat. No. 3,904,685) and have been included as part ofbuilder systems in commercial tablet and opaque gel ADW formulations.Their carboxylic acid/carboxylate groups allow them to chelate or formsalts with the metal ions. As polyelectrolytes, they can also act asdispersants for soils, helping to prevent their redeposition on glassand dishware. For instance, compounds in the Sokalan™ PA range areadvertised as dispersants. On the other hand, other types of polyacrylicacid may not have builder capacity, depending on the polymer structure.For example, cross-linked, high molecular weight polyacrylic acid (e.g.in the Carbopol™ range) has been used in low concentrations as athickener for aqueous liquid ADW systems, together with anon-cross-linked, lower molecular weight polyacrylic acid salt as abuilder (cf. U.S. Pat. No. 5,368,766).

Typically, a polyacrylic acid builder is synthesised in aqueoussolution, and optionally then dried. Thus, the common forms that arecommercially available to the detergent formulator are an aqueous liquidor a spray-dried powder. The formulator may use the powder directly in atablet formulation, use the aqueous liquid directly in an aqueous liquiddetergent formulation, or redissolve the powder in an aqueous liquiddetergent formulation. However, there is great difficulty in dissolvinghigh levels of polyacrylic acid builder in non-aqueous systemscomprising high levels of non-ionic surfactants. Copolymers of acrylicacid and other monomers that have been tried may have a greatersolubility in the surfactant composition, but show lower solubility inthe wash liquor and lower performance as a builder.

WO 2004/099274 discloses the formation of a graft polymer in which apolyalkylene glycol forms the backbone, and poly(meth)acrylic acid isgrafted as branches onto the backbone. Use of the graft polymer inautomatic dishwashing is mentioned. The free radical polymerisation iscarried out at 90° C. in the presence of the polyalkylene glycol andwater which is charged into the system at a controlled time. The graftpolymer is therefore formed in an aqueous system, which may optionallyadditionally contain an organic solvent. Accordingly, this could not beused directly to form a non-aqueous gel.

EP 0,639,592 discloses the formation of a builder which is a relatedgraft polymer to the one of WO 2004/099274. The polymerisation reactionis carried out at 100° C. or higher in the presence of substantially nosolvent of any type; the polyether is melted by heating, to allow thereaction to take place. The ratio of monomers to polyether is at least0.25:1. Although the polymerisation reaction itself does not utilise asolvent, the polymer is subsequently neutralised using an aqueous baseor dissolved in a water/alcohol mixture, such that the end result of thesynthesis is an aqueous solution of the graft polymer. Accordingly, itcould not be used directly in non-aqueous gels. Furthermore, theexamples of detergents in this document are aqueous liquid detergents.

There is still a need in the art for a transparent/translucent,non-aqueous ADW gel containing significant quantities of a builder,preferably a self-standing gel of this type. Such a gel would beadvantageous even when not incorporated in a water soluble container,for example if the gel is rigid and stable enough not to requireencapsulation in a container.

The present inventors have discovered that polyacrylic acid and relatedacrylates can be synthesised directly in non-ionic surfactant, in theabsence of water, to form an aesthetically appealing gel that issuitable for ADW use and affords good builder and surfactantperformance.

SUMMARY OF THE INVENTION

In a first aspect of the invention there is provided a method ofmanufacturing an automatic dishwashing detergent product, said productbeing provided as a discrete dosage unit and comprising a continuous,non-aqueous gel phase, comprising manufacturing said gel phase by amethod comprising free radical polymerisation of monomer(s) in anon-aqueous reaction mixture to form a polymeric builder; wherein saidreaction mixture comprises: at least one non-ionic surfactant which isan optionally end-capped alcohol alkoxylate; and one or more monomerscomprising acrylic acid and optionally one or more furtherα,β-ethylenically unsaturated acids, wherein no more than 0.1 wt % ofthe total amount of the monomer(s) are crosslinking monomer(s).

In a second aspect of the invention there is provided an automaticdishwashing detergent product provided as a discrete dosage unit,obtainable by the method according to the invention in its first aspect.

In a third aspect of the invention there is provided an automaticdishwashing detergent product provided as a discrete dosage unit,comprising a continuous, non-aqueous gel phase, said gel phasecomprising at least 10 wt % non-ionic surfactant and at least 20 wt %polymeric builder; wherein: said non-ionic surfactant is one or moreoptionally end-capped alcohol alkoxylates; and said polymeric builder ismade by the free radical polymerisation, in a non-aqueous liquidcomprising said non-ionic surfactant, of acrylic acid and optionally oneor more further α,β-ethylenically unsaturated acids; and said polymericbuilder is at least substantially non-crosslinked and has a weightaverage molecular weight of no more than 70,000.

In a fourth aspect of the invention there is provided an automaticdishwashing process using the product according to the invention in itssecond or third aspect.

In a fifth aspect of the invention there is provided the use of theproduct according to the invention in its second or third aspect forautomatic dishwashing.

DETAILED DESCRIPTION

Overview of Product Type

The product manufactured in the invention is a discrete dosage unit andthe consumer can conveniently apply it to an automatic dishwashingprocess without needing to manually measure out the required amount ofdetergent, unlike with bulk gels or powders. However, although it ispreferable for only one such discrete dosage unit to be applied at atime, it is possible that a consumer may dose a plurality (generally 2or 3) of discrete dosage units simultaneously. Preferably, the discretedosage unit is designed to complete its function during a single run ofthe dishwasher (e.g. when the discrete dosage unit comprises a main washdetergent, and optionally also a rinse aid).

The discrete dosage unit comprises a non-aqueous gel phase which iscontinuous in the normal sense of the word. Accordingly, finely dividedgel pieces mixed into a particulate solid composition, or dispersed in aliquid, are not considered to be a continuous gel phase.

Overview of Gel Phase Manufacture

The method of producing the gel phase used in the invention comprisessubjecting one or more monomers to free radical polymerisation in thepresence of at least one non-ionic surfactant, in a non-aqueous reactionmixture. Preferred ingredients of the reaction mixture are discussedbelow.

Preferably, the composition at the end of the polymerisation reaction isalready in a gelled state or is capable of gelling directly uponcooling. In other words, the method involves forming the gel phase inthe invention without an intermediate step of drying this composition toform a solid comprising the polymeric builder. Previously, a solidbuilder of this type would have needed to be re-dissolved in an aqueoussurfactant-containing system, so the resulting gel would be an aqueousone. In contrast, the present invention allows the builder to besynthesised directly together with the non-ionic surfactant and to be ina dissolved state in the resulting composition, which allows theeventual non-aqueous gel to be transparent or translucent, if desired,whilst still including a high concentration of these ingredients.

The free radical polymerisation thus forms a composition with advantagesfor the formulation of a non-aqueous gel with surfactant and builderproperties in automatic dishwashing. Without being bound by theory, thismay, for example, be due to an effect of the surfactant as a protectivecolloid or emulsifier. It is possible that at least a proportion of thepolymeric builder exists as a graft polymer comprising both thenon-ionic surfactant and polymerised monomers. However, it is preferablefor a relatively low proportion (e.g. less than 20%) of the polymericbuilder to be in the form of a graft polymer. In an embodiment, none ofthe polymeric builder is a graft polymer. It is theorised that if thepolymeric builder is in the form of a graft polymer with the non-ionicsurfactant, its builder performance may be more limited due to sterichindrance restricting its ability to interact with metal ions. Secondaryactivity as a soil dispersant may also be inhibited. On the other hand,it is also advantageous if the builder and non-ionic surfactant areseparable so that, for instance, some of the non-ionic surfactant canpotentially carry over into the rinse cycle without some or all of thebuilder carrying over too.

Although a solid form of the polymeric builder need not be separated outfrom the composition at the end of the polymerisation reaction, furthersteps may still advantageously be comprised in the method of theinvention in between completion of the polymerisation reaction andprovision of the discrete dosage unit comprising the gel phase. Forexample, other ingredients, e.g. dyes, which may be sensitive to thepolymerisation reaction conditions, may be added to the compositionafter the polymerisation has completed. In an embodiment, the gel phaseis thermoreversible. Thus, the composition at the end of thepolymerisation may be cooled, forming a gel, which is then reheated toform a lower viscosity liquid and allow the homogeneous incorporation offurther ingredients, and subsequently re-cooled to form the gel phase.

The polymerisation reaction will now be described in more detail.

Reaction Mixture Ingredients

Non-Ionic Surfactant

The polymerisation reaction mixture comprises at least one non-ionicsurfactant, which is an optionally end-capped alcohol alkoxylate.Preferably, it is low-foaming.

The non-ionic surfactant may be e.g. one that is solid at roomtemperature, but liquid at the polymerisation temperature. In anembodiment, the non-ionic surfactant is a liquid at 20° C.; this ispreferred from the perspective of allowing transparency of the resultinggel. A mixture of non-ionic surfactants may be used, including a mixtureof solid and liquid non-ionic surfactants, in which case a predominanceof the liquid one(s) is preferred. Preferably, at least 50 wt %,preferably at least 60 wt %, 70 wt %, 80 wt %, 90 wt %, or all, of thenon-ionic surfactants are liquid at 20° C.

In an embodiment, the non-ionic surfactant is a mono- or di-(C₁-C₆alkyl)ether of a polyether polyol.

In an embodiment, the non-ionic surfactant comprises ethoxylate groups.In an embodiment the only alkylene oxide groups in the non-ionicsurfactant are ethoxylate groups. In another embodiment, the non-ionicsurfactant comprises propylene oxide groups and/or butylene oxidegroups, in addition to ethylene oxide groups.

In an embodiment, the optional end cap is a hydroxylated alkyl group,preferably a CH₂CH(OH)R group in which R is alkyl.

In an embodiment, the non-ionic surfactant is of the formulaR¹—O—(R²—O)_(x)—(R³—O)_(y)—R⁴, in which:

-   -   R¹ and R⁴ are independently H, optionally substituted alkyl or        optionally substituted alkenyl, provided that both R¹ and R⁴ are        not H;    -   R²—O and R³—O are different but each independently ethylene        oxide, propylene oxide or butylene oxide; and    -   x and y are independently between 0 and 300 (representing the        average degree of alkoxylation), with the proviso that at least        one of x and y is non-zero.

Where x and y are both non-zero, the order of R²—O and R³—O groups maybe varied such that this represents a random or block copolymer.

Preferably, one or more of the following criteria apply:

-   -   R¹ and R⁴ are independently H or optionally substituted alkyl,        preferably H or optionally hydroxylated alkyl, preferably H or        C₁-C₃₀ alkyl;    -   R¹ is C₃-C₂₅ alkyl, preferably C₄-C₂₂ alkyl, preferably C₅-C₂₀        alkyl, preferably C₆-C₁₈ alkyl, preferably C₇-C₁₅ alkyl;    -   R⁴ is H or C₁-C₁₀ alkyl, preferably H or C₂-C₆ alkyl, preferably        H or C₃-C₄ alkyl;    -   R²—O is ethylene oxide and x is non-zero, but if R³—O is        present, the order of alkoxylate groups may be varied;    -   x and y are independently between 0 and 100, preferably between        0.5 and 70, preferably between 0.7 and 50, preferably between        0.9 and 30, preferably between 1 and 20, preferably between 1.5        and 10;    -   the sum of x and y is at least 3, preferably at least 4,        preferably at least 5;    -   R²—O is ethylene oxide and x is at least 3, preferably at least        4, at least 5, or at least 6;    -   R²—O is ethylene oxide, both x and y are non-zero, and x is        greater than y, preferably x is at least double y;    -   if R⁴—O is propylene oxide and y is non-zero, y is 18 or less,        preferably 17 or less, preferably 15 or less, preferably 10 or        less.

In an embodiment, the reaction mixture comprises at least 10 wt %,preferably at least 15 wt %, preferably at least 18 wt %, preferably atleast 20 wt %, in total of the non-ionic surfactant(s). Preferably, thetotal amount of the non-ionic surfactant(s) in the reaction mixture isup to 50 wt %, preferably up to 45 wt %, up to 40 wt %, up to 35 wt %,up to 30 wt %, or up to 25 wt %.

Monomers

The polymerisation reaction mixture also comprises acrylic acid, but isfree from any significant amount of crosslinking monomer. Crosslinkingmonomers include monomers having two unsaturated bonds per molecule.Preferably, the total amount of any crosslinking monomer(s) used is nomore than 0.05 wt %, preferably no more than 0.01 wt %, preferably nomore than 0.005 wt %, preferably no more than 0.001 wt %, based on thetotal weight of all the monomers used. Preferably, no crosslinkingmonomer is used at all. As discussed above, polyacrylic acid that issignificantly crosslinked may act as just a thickener, without buildercapability.

The acrylic acid monomer is preferably not in the form of an acrylatesalt. The unneutralised acid form is a liquid at 20° C. and so itsphysical state does not hinder its polymerisation. Salts like sodiumacrylate, on the other hand, are solids with high melting points.

Optionally, the reaction mixture includes one or more furtherα,β-ethylenically unsaturated acid monomers, aside from the acrylicacid; preferably a hydrophilic/water-soluble monomer. The furtherα,β-ethylenically unsaturated acid monomer(s) should be soluble in thereaction mixture. Suitable further monomers include a α,β-ethylenicallyunsaturated carboxylic acid, sulphonic acid or phosphonic acid,preferably a α,β-ethylenically unsaturated carboxylic acid, preferablymethacrylic acid, ethacrylic acid, maleic acid, crotonic acid, itaconicacid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid,or fumaric acid. Preferably none of the monomers contain phosphorusatoms (“P-free”).

In an embodiment, the reaction mixture includes a mixture of acrylicacid and a αβ-ethylenically unsaturated dicarboxylic acid of theformula:

wherein one of R¹, R² and R³ is C_(m)H_(2m)CO₂H wherein m is 0, 1, 2 or3, preferably 0 or 1; and the others of R¹, R² and R³ are independentlyH or C_(n)H_(2n+1) wherein n is 1, 2 or 3, preferably 1. Preferably, oneof R¹, R² and R³ is H.

If such further monomer is used, preferably the weight ratio of acrylicacid to said one or more further α,β-ethylenically unsaturated acids inthe reaction mixture is in the range of 100:1 to 1:1, preferably 50:1 to5:1, preferably 30:1 to 10:1.

In an embodiment, the amount of acrylic acid as a proportion of thetotal monomer content in the reaction mixture is at least 50 wt %, atleast 55 wt %, at least 60 wt %, at least 65 wt %, at least 68 wt %, orat least 70 wt %. Preferably, the amount of acrylic acid as a proportionof the total monomer content in the reaction mixture is up to 90 wt %,up to 85 wt %, up to 80 wt %, or up to 75 wt %.

In an embodiment, the reaction mixture includes acrylic acid anditaconic acid. In an embodiment, no other monomers are used apart fromthe combination of acrylic acid and itaconic acid. In an embodiment, theamount of itaconic acid as a proportion of the total monomer content inthe reaction mixture is at least 10 wt %, at least 15 wt %, at least 20wt %, at least 25 wt %, at least 28 wt %, or at least 30 wt %.Preferably, the amount of itaconic acid as a proportion of the totalmonomer content in the reaction mixture is up to 50 wt %, up to 45 wt %,up to 43 wt %, or up to 40 wt %.

In an embodiment, the weight ratio of acrylic acid to itaconic acid inthe reaction mixture is: at least 1:1, at least 1.1:1, at least 1.2:1,at least 1.3:1, at least 1.4:1, at least 1.5:1, at least 1.6:1, at least1.7:1, at least 1.8:1, at least 1.9:1, at least 2:1, at least 2.1:1, atleast 2.2:1, or at least 2.3:1; and/or up to 3:1, up to 2.9:1, up to2.8:1, up to 2.7:1, up to 2.6:1, up to 2.5:1, or up to 2.4:1.

In an embodiment, the only monomer in the reaction mixture is acrylicacid.

In an embodiment, the reaction mixture comprises at least 20 wt %,preferably at least 25 wt %, at least 30 wt %, at least 35 wt %, or atleast 40 wt %, in total of the monomer(s). Preferably, the total amountof the monomer(s) in the reaction mixture is up to 70 wt %, preferablyup to 65 wt %, up to 60 wt %, up to 55 wt % or up to 50 wt %.

Solvent

The reaction mixture is non-aqueous, in other words it comprisessubstantially no water, preferably no more than 10 wt % water,preferably no more than 9 wt %, 8 wt %, 7 wt %, 6 wt %, 5 wt %, 4 wt %,3 wt %, 2 wt %, or 1 wt % water. Preferably, the reaction mixturecontains no water at all. However, small amounts of water may beunavoidable, for instance if an initiator, chain transfer agent or otherreactant to be used in small quantities can only suitably be deliveredin aqueous solution.

On the other hand, bulk polymerisation (in the absence of any solvent atall) can be difficult to control due to lack of effective heat transferand rapid viscosity increase as the reaction progresses. Accordingly,the use of at least one non-water solvent is desirable. In anembodiment, the reaction mixture comprises a polar/water-soluble organicsolvent, preferably a glycol, preferably an alkylene glycol ordialkylene glycol, preferably monopropylene glycol or dipropyleneglycol, preferably dipropylene glycol. Other alternative solventsinclude alcohols, such as C₁-C₆ alcohols.

The solvent may be one with a relatively low vapour pressure at thepolymerisation reaction temperature, such that the weight loss ofsolvent during the polymerisation reaction is relatively low. In anembodiment, the solvent has a vapour pressure of less than 1 kPa at 25°C. and 1 atm pressure, preferably less than 0.1 kPa, preferably lessthan 0.01 kPa.

In an embodiment, the reaction mixture comprises the one or morenon-water solvents in a total amount of at least 10 wt %, preferably atleast 15 wt %, at least 20 wt % solvent, at least 25 wt %, or at least30 wt %. Preferably, the total amount of non-water solvent(s) is up to60 wt %, preferably up to 55 wt %, up to 50 wt %, up to 45 wt %, up to40 wt % or up to 35 wt %.

In the embodiment in which a mixture of acrylic acid and aα,β-ethylenically unsaturated dicarboxylic acid of the formula:

is used, the reaction mixture preferably comprises the one or morenon-water solvents in a total amount of: at least 30 wt %, preferably atleast 35 wt %, preferably at least 38 wt %, preferably at least 40 wt %;and/or up to 60 wt %, preferably up to 55 wt %, preferably up to 53 wt%, preferably up to 50 wt %.

In an embodiment, less than 20 wt % of the solvent in the reactionmixture is lost (e.g. by evaporation) during the polymerisationreaction, preferably less than 15 wt %, 10 wt % or 5 wt %.

Increasing the monomer concentration in the reaction mixture will tendto increase the viscosity of the composition formed at the end of thepolymerisation reaction, whereas increasing the concentration of solventwill tend to decrease its viscosity. Thus, the viscosity can be tailoredto the desired application by, inter alia, selecting the appropriateconcentration of ingredients in the reaction mixture.

Initiator

The polymerisation reaction usually utilises at least one free radicalpolymerisation initiator. The initiator desirably acts in solution.Suitable initiators include ones having a peroxo group or azo group.Examples include alkali metal- or ammonium-peroxidisulphate, diacetylperoxide, dibenzoyl peroxide, succinyl peroxide, di-tert-butyl peroxide,tert-butylperbenzoate, tert-butylperoxypivalate,tert-butylperoxy-2-ethylhexanoate, tert-butylpermaleinate, cumenehydroperoxide, di-isopropylperoxidicarbamate, bi-(o-toluoyl)-peroxide,didecanoylperoxide, dioctanoylperoxide, tert-butylperoctoate,dilauroylperoxide, tert-butylperisobutyrate, tert-butylperacetate,di-tert-amylperoxide, tert-butylhydroperoxide,2,2′-azo-bis-isobutyronitrile, azo-bis-(2-amidinopropan)dihydrochloride,azobis(2,4-dimethylvaleronitrile) or2,2′-azo-bis-(2-methyl-butyronitrile).

The initiator is selected to give an appropriate reaction speed at thereaction temperature. Preferably, the initiator is an organic peroxide,preferably an alkyl peroxyester.

Also suitable are initiator mixtures or redox initiator systems, suchas: ascorbic acid/iron (II) sulphate/sodium peroxodisulphate;tert-butylhydroperoxide/sodium disulphite;tert-butylhydroperoxide/sodium hydroxymethanesulphinate; H₂O₂/Cu^(I).

In the inventive method, the total amount of initiator(s) used in thereaction mixture is preferably in the range of 0.01-10 wt %, preferably0.05-5 wt %, 0.08-2 wt %, 0.1-1.5 wt %, 0.2-1.0 wt % or 0.3-0.9 wt %. Anincrease in the level of initiator may affect the reaction speed andtypically acts to decrease the molecular weight of the resultingpolymer.

The initiator may be supplied to the reaction mixture in its nativestate or, more usually, pre-mixed with a solvent, preferably at leastone solvent selected from the non-water solvents outlined above.

Chain Transfer Agent

The polymerisation reaction mixture desirably includes at least onechain transfer agent, in order to reduce the molecular weight of thepolymeric builder obtained without adversely affecting the overallreaction rate. Suitable chain transfer agents are known in the art, forinstance as described in detail in Polymer Handbook, 3^(rd) Edition [JBrandrup & E. H. Immergut], John Wiley & Sons, New York, 1989, p.II/81-II/141.

The chain transfer agent may be mono- or multi-functional.

The chain transfer agent is, for example, an aldehyde, such asformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, orisobutyraldehyde. Other suitable chain transfer agents include formicacid and its salts or esters, such as ammonium formate,2,5-diphenyl-1-hexene, hydroxylamine sulfate, and hydroxylammoniumphosphate. Further suitable chain transfer agents are halogen compounds,e.g. alkyl halides such as carbon tetrachloride, chloroform,bromotrichloromethane, bromoform, allyl bromide, and benzyl compounds,such as benzyl chloride or benzyl bromide. Further suitable chaintransfer agents are allyl compounds such as allyl alcohol,functionalised allyl ether such as allyl ethoxylates, alkylallyl etheror glycerol monoallylether.

Preferably, the chain transfer agent is not a phosphate, and preferablyit is P-free. Preferably, the chain transfer agent is asulphur-containing compound. Compounds of this type are, for example,inorganic hydrogen sulphite, disulphites and dithionites or organicsulphides, disulphides, polysulphides, sulphoxides and sulphones. Theseinclude di-n-butyl sulphide, di-n-octyl sulphide, diphenyl sulphide,thiodiglycol, ethylthioethanol, diisopropyldisulphide,di-n-butyldisulphide, di-n-hexyldisulphide, diacetyldisulphide,di-ethanol sulphide, di-t-butyl trisulphide, dimethyl sulphoxide,dialkyl sulphide, dialkyl disulphide and/or diaryl sulphide.

Preferred chain transfer agents include thiols (compounds comprising —SHgroups, also known as mercaptans). Alkyl mercaptans may be used such asn-butyl mercaptan, n-hexyl mercaptan or n-dodecyl mercaptan. Preferenceis given to chain transfer agents which are mono-, bi-, andpolyfunctional mercaptans. Examples of bifunctional chain transferagents are those that contain two sulfur atoms, such as bifunctionalthiols like dimercaptopropanesulfonic acid (sodium salt),dimercaptosuccinic acid, dimercapto-1-propanol, dimercaptoethane,dimercaptopropane, dimercaptobutane, dimercaptopentane,dimercaptohexane, ethylene glycol-bis-thioglycolate andbutane-bis-thioglycolate. Examples of polyfunctional chain transferagents are compounds which contain more than two sulfur atoms, such astrifunctional and tetrafunctional mercaptans.

In an embodiment, the at least one chain transfer agent comprises amercapto alcohol, mercapto carboxylic acid and/or mercapto carboxylicacid ester. Examples of these compounds are allyl thioglycolates, ethylthioglycolate, cysteine, 2-mercaptoethanol, 3-mercapto-1-propanol,3-mercaptopropan-1,2-diol, 4-mercapto-1-butanol, mercaptoacetic acid,3-mercaptopropionic acid, mercaptosuccinic acid, and thioglycerine.

The total amount of chain transfer agent in the reaction mixture,relative to the total amount of monomer(s), is preferably in the rangeof 1-40 pphm i.e. parts by weight per hundred parts by weight of thetotal amount of monomer(s). Preferably, the amount of chain transferagent is 3-30 pphm, preferably 5-25 pphm.

The total amount of chain transfer agent in the whole reaction mixtureis preferably up to 15 wt %, preferably up to 12 wt %, or up to 10 wt %.The total amount is preferably at least 0.1 wt %, at least 0.5 wt %, atleast 1 wt %, or at least 2 wt %.

Preferably, the entire reaction mixture is phosphate-free. Preferably,it is P-free.

Reaction Conditions

The free radical polymerisation is preferably conducted at a temperatureof up to 90° C., preferably up to 85° C. or 80° C. Preferably, thepolymerisation reaction temperature is at least 20° C., preferably atleast 30° C., at least 40° C., at least 50° C., at least 60° C., or atleast 70° C. Preferably, the polymerisation is carried out at constantor substantially constant temperature, but if desired it may be variedduring the reaction.

Preferably, the polymerisation is carried out at ambient pressure.

The polymerisation can be carried out in the presence or absence of aninert gas, such as nitrogen or argon.

The free radical polymerisation is desirably conducted in a feed mode ofoperation. This means that, of all the raw materials used for thereaction, a portion may be included as an initial charge in a reactionvessel, and the remainder may be fed to the vessel over a period oftime, whilst the reaction progresses. Accordingly, where a wt % amountof a raw material in the reaction mixture is quoted herein, this relatesto the amount used as a proportion of the total amount of raw materialssupplied to the entire polymerisation reaction, and it will beunderstood that this does not necessarily correlate with the actualconcentration in the reaction vessel, either at the start of thereaction or at a later point during the reaction.

The initial charge in the reaction vessel preferably includes at least aportion of the non-ionic surfactant(s) and optionally at least a portionof the solvent. Preferably the initial charge does not include anymonomer and/or initiator.

When a chain transfer agent is used, preferably none or only a portionof it is included in the initial charge. Preferably, all of the chaintransfer agent that is used is supplied in a feed.

The feed(s) are preferably selected to achieve the desired conversionrate for the polymerisation. Individual feeds can be suppliedcontinuously or at intervals, with constant or variable flow rate, andmultiple feeds can be supplied simultaneously or at different times.Preferably, the feed(s) are supplied simultaneously, continuously andwith as constant as possible a flow rate. Typically, the initial chargeis heated with stirring to the polymerisation temperature prior to theaddition of the feed(s).

Preferably the feed(s) are supplied to the reaction vessel over a periodof 1 to 10 hours, preferably 2 to 8 hours, preferably 3 to 5 hours,preferably 3.5 to 4.5 hours. Preferably, once all the feed(s) have beensupplied to the reaction vessel, the temperature is maintained at thepolymerisation temperature for at least 30 minutes, preferably at least45 minutes, preferably at least an hour.

After completion of the polymerisation, the composition is optionallycooled, for example to 20° C.

In an embodiment, acid groups are partially or completelynon-neutralised in the polymeric builder. Preferably, the method of theinvention does not involve neutralisation of acid groups, either via apost-polymerisation neutralisation step or via neutralisation during thepolymerisation reaction.

Preferably, there is no other step employed which would causecrosslinking of the polymeric builder, e.g. involvingpost-polymerisation heat treatment, irradiation or chemicalcrosslinking.

Formation of the Continuous Gel Phase and its Properties

As discussed above, the composition at the end of the polymerisationreaction is preferably already in a gelled state or is cooled to form agel. This composition may therefore contain residual components from thepolymerisation reaction as impurites, such as residual initiator, chaintransfer agent and/or monomer. It may be used directly as the continuousgel phase in the invention, or additional ingredients may be added toform the final gel phase, before or after any cooling step.

Such additional ingredients may include, for example, additionalsolvent, non-ionic surfactant or thickener, to adjust the viscosity, andminor additives such as dyes or fragrances. However, preferably noadditional solvent, surfactant or thickener is added (save for minoramounts of solvent which may be used for delivery of dyes and/orfragrances).

In an embodiment, the gel phase in the discrete dosage unit does notinclude any ionic surfactant, builder (apart from the polymericbuilder), enzyme, and/or bleach. Such optional ingredients can beincluded in other parts of the discrete dosage element, if required.

In an embodiment, any ingredients added after the polymerisation stagemake up a total amount of no more than 15 wt % of the final gel phase,preferably no more than 12 wt %, no more than 10 wt %, no more than 8 wt%, no more than 5 wt %, no more than 3 wt %, or no more than 1 wt %, ofthe final gel phase. Accordingly, the concentration of a component inthe gel phase in the discrete dosage unit may be within the same rangeas quoted above for the level of the corresponding component in thereaction mixture.

Preferably, the gel phase in the discrete dosage unit comprises 5-50 wt%, preferably 20-30 wt %, non-water solvent. The water level of the gelphase may be slightly increased compared to the reaction mixture, e.g.due to the subsequent addition of dyes in aqueous solution. However, thecontinuous gel phase is still non-aqueous, preferably in the sense thatit contains no more than 6 wt % water, preferably no more than 5 wt %, 4wt %, 3 wt %, 2 wt or 1 wt % water.

Determining the amount of non-ionic surfactant and polymerised monomersin the gel may be complicated in the event that there is at leastpartial formation of a graft polymer. However, it may be possible toestimate this e.g. by inference from the level of ingredients in thereaction mixture and knowledge of the reaction system.

In an embodiment, the gel phase comprises 10-50 wt % non-ionicsurfactant, preferably 15-30 wt non-ionic surfactant. In an embodiment,the gel phase contains at least 20 wt % of the polymeric builder,preferably at least 25 wt %, at least 30 wt %, at least 35 wt %, or atleast 40 wt % of the builder. Preferably, the gel phase contains up to60 wt %, up to 55 wt % or up to 50 wt % of the builder.

The weight average molecular weight of the polymeric builder may bedetermined by gel permeation chromatography using neutralisedpolyacrylic acid as a polymer standard. The eluent is 0.08 mol/l Tris,pH 7.0+0.15 mol/l NaCl+0.01 mol/l NaN₃ in deionised water, with a flowrate of 0.8 ml/min. The column set is one guard column (1=5 cm) and 2separation columns (1=30 cm each), and the column temperature is 35° C.The detector is a DRI (refractive index detector) Agilent 1100.

In an embodiment, the weight average molecular weight of the polymericbuilder, as determined by the above method, is in the range of1000-70000 g/mol, preferably 1500-50000 g/mol, preferably 1800-10000g/mol, preferably 2000-9000 g/mol, 3000-8000 g/mol, 3500-7500 g/mol, or4000-7300 g/mol. Preferably, when the polymeric builder is made fromacrylic acid as the only monomer, the weight average molecular weight isno more than 10000 g/mol. Copolymers may have a higher molecular weight.The molecular weight of the polymeric builder can be controlled in amanner known in the art e.g. using a chain transfer agent in a suitableamount, and/or controlling the amount and type of initiator, asdiscussed above.

In the embodiment in which a mixture of acrylic acid and aα,β-ethylenically unsaturated dicarboxylic acid of the formula:

is used, the weight average molecular weight of the polymeric builder ispreferably: at least 5000 g/mol, at least 7000 g/mol, at least 10000g/mol, at least 15000 g/mol, at least 20000 g/mol, at least 25000 g/mol,at least 30000 g/mol, at least 35000 g/mol, at least 40000 g/mol, atleast 43000 g/mol, at least 45000 g/mol, or at least 48000 g/mol; and/orup to 65000 g/mol, up to 63000 g/mol, up to 60000 g/mol, up to 55000g/mol, up to 53000 g/mol, or up to 50000 g/mol.

Preferably up to 40 mol %, 30 mol %, 20 mol %, 10 mol %, 5 mol %, ornone, of the acid groups in the polymeric builder are in neutralisedform. In an embodiment, the polymeric builder has a content of acidgroups of 1.5 to 15 mmol/g, preferably 2 to 10 mmol/g, preferably 3 to 8mmol/g, preferably 4 to 7 mmol/g.

In an embodiment, the gel phase is phosphate free. In an embodiment, itis P-free.

The following properties of the gel phase are determined at 20° C., 1bar pressure, unless otherwise stated.

Ideally the viscosity of the gel phase should be selected to achieve abalance between speed of dissolution in the wash and reduced rate ofleakage out of a ruptured container or packaging. Whilst appreciatingthat the chemical nature of the gel will also affect its solubility, aless viscous gel will tend to exit a container faster during the wash,upon dissolution of the surrounding container material. The desire for ahigh content of actives will also be an influencing factor.

In an embodiment, the gel phase has a viscosity of at least 200 mPa·s,preferably at least 400 mPa·s, at least 600 mPa·s, at least 800 mPa·s,at least 1000 mPa·s, at least 1500 mPa·s, at least 2000 mPa·s, at least5000 mPa·s, at least 10,000 mPa·s, at least 20,000 mPa·s, at least30,000 mPa·s, or at least 50,000 mPa·s.

In an embodiment, the gel phase has a viscosity of at least 100,000mPa·s, at least 500,000 mPa·s, at least 1,000,000 mPa·s, at least5,000,000 mPa·s, or at least 10,000,000 mPa·s, at 20° C. as measuredwith a rotational rheometer (DHR-1 TA-Instruments, parallel discs, Ø40mm, h=1 mm).

In an embodiment, the gel phase is self-standing, and does not flow at20° C., 1 atm pressure. Such a gel is too viscous for reliable viscositymeasurements to be made at 20° C. using a device such as a Brookfieldviscosimeter.

The gel phase may be thermoreversible, and its viscosity when heated to50° C. may desirably be less than 5000 mPa·s, less than 1000 mPa·s, lessthan 500 mPa·s, or less than 200 mPa·s, as measured with a Brookfieldviscosimeter. This facilitates e.g. its filling into a container whenheated to a pourable, lower viscosity liquid, and cooling to form ahigher viscosity gel phase, especially a self-standing gel, which itwould not be possible to pour at room temperature.

In an embodiment, the continuous gel phase is translucent ortransparent, preferably transparent. Transparency and translucency canbe visually observed by the skilled person. In an embodiment, thecontinuous gel phase is colourless and has a light transmission levelT_(L) (amount of transmitted light as a percentage of incident light) at500 nm of at least 70%, preferably at least 75%, preferably at least80%, preferably at least 85%, preferably at least 87%, preferably atleast 90%, relative to distilled water which is designated as having aT_(L) of 100%. In another embodiment, it is a coloured gel due to theinclusion of a dye or other colourant, however in the absence of thecolourant it would be a colourless gel having a light transmission levelat 500 nm of at least 70%, preferably at least 75%, preferably at least80%, preferably at least 85%, preferably at least 87%, preferably atleast 90%, compared to distilled water.

The desirable speed of dissolution in the wash depends on the desireduse. In an embodiment, the discrete dosage unit is adapted to dissolveduring a single run of the dishwasher. A dishwasher “run” is understoodas one complete dishwasher program, which may include one or more washcycles, rinse cycles, etc.

In an embodiment, the continuous gel phase has a dissolution time inwater of 20 minutes or less according to the method described below,preferably 19, 18, 17, 16, 15, 14, 13, 12, 11 or 10 minutes or less.Such a gel phase is suitable for use in a discrete dosage unit to beconsumed in a single dishwasher run.

A 1 l glass beaker is filled with 800 ml water which is at 45° C. andhas a hardness of 18° gH. The beaker is equipped with a magnetic stirrerbar rotating at 250 revolutions per minute. A 2 g cube of gel is placedinside a metal tea strainer of the clam-shell type (diameter 4 cm, 1 mmholes in the mesh) and immersed in the water above the stirrer bar. Thetime it takes for the gel to be fully dissolved (by visual inspection,no gel left inside the tea strainer) is measured.

Discrete Dosage Unit Format

The discrete dosage unit may comprise a container containing the gelphase. Preferably, a composition is filled into the container and cooledto form the gel phase. Alternatively, if the gel phase used in theinvention is self-standing, it need not be filled into a container to beprovided as a discrete dosage unit, but may serve alone as the discretedosage unit.

If the discrete dosage unit comprises a container, this is preferably awater-soluble container. Known processes for manufacturing containersfrom water-soluble materials include thermoforming, vacuum-forming,vertical form-fill-sealing, horizontal form-fill-sealing, and injectionmoulding. In an embodiment, the container is made by injection moulding.

The walls of the container may be made from the same or differentcontainer materials. If they are made of the same material, they may beof different thicknesses. If they are made of different materials, theymay be of different thicknesses and/or the materials may have adifferent inherent solubility.

The materials typically comprise a water-soluble polymer and optionallyone or more additives as is known in the art, e.g. plasticiser, fillerand so on.

Suitable polymers are polyvinyl alcohols, polyvinyl acetates, cellulose,cellulose ethers, and polysaccharides such as starch and gelatine.Preferred are polyvinyl alcohols, polyvinyl alcohol copolymers andhydroxylpropyl methyl cellulose, and combinations thereof. Mostpreferably the container material(s) comprise PVOH or a PVOH copolymer.Partially hydrolysed PVOH, as is known in the art, is particularlysuitable. The container material(s) may comprise a blend of polymers,e.g. a blend of PVOH polymers of different grades.

The discrete dosage unit may have any suitable size and shape overall.If it is designed to be dispensed from the dispenser compartment of thedishwasher, to make most efficient use of the available space, thecontainer preferably has a cuboidal shape, e.g. a cube or a rectangularcuboidal shape, preferably a rectangular cuboidal shape. It will beunderstood in the context of the invention that these terms do not implymathematical precision; slight bulges of the faces and rounding of theedges may be expected, consistent with the flexible nature of thecontainer material(s) and pressure exerted by the contents.

In an embodiment, the total volume of the discrete dosage unit is 40 mlor less, preferably 35 ml or less, preferably 30 ml or less, preferably25 ml or less, preferably 20 ml or less. Suitably the longest dimensionof the discrete dosage unit is in the range of 2 to 6 cm, preferably 2.5to 5 cm, preferably 3 to 4 cm.

If the discrete dosage unit is designed to be used outside the dispensercompartment, it is less restricted in size and shape.

In an embodiment, the discrete dosage unit is a container comprising atleast 2 compartments. In an embodiment, the container has 2 or 3compartments. Each compartment of the multi-compartment container mayindependently comprise any suitable form of composition, includingsolid, liquid, gel, paste, provided that at least one compartmentcontains the continuous gel phase of the invention. In an embodiment,the container contains the continuous gel phase of the invention in atleast one compartment, and a solid composition in at least one further,separate compartment. Preferably, this solid composition is aparticulate solid, preferably a powder. Thus, desirable solid componentsof the overall detergent to be supplied (such as solid builder, bleach,enzymes, etc.) can be included in the container in high amounts, withoutthe formulation problems of trying to include them in the gel phase ofthe invention.

In another embodiment, the container has at least three compartments,one containing a transparent or translucent gel phase of the invention,one containing an opaque gel, and one containing a solid, especiallypowder, composition. Thereby both solid and liquid ingredients can beutilised which might otherwise suffer from difficulties in formulatingthem in the inventive gel phase.

If aqueous gels or liquids are contained in a compartment that shares awall with another compartment in the container, water is liable tomigrate through the container wall. This can cause adverse interactionse.g. degradation of a moisture-sensitive ingredient in the othercompartment (such as a bleach or an enzyme), and/or swelling of aparticulate solid formulation in the other compartment, causing it toburst the compartment walls. Thus, use of the non-aqueous gel phase ofthe invention brings an additional advantage in this instance.

Optional Ingredients in Other Parts of the Dosage Unit

Optional dishwashing ingredients which may be included in the discretedosage unit, but preferably not in the continuous gel phase, are knownin the art. Mention may be made of, for example, one or more furtherbuilders (other than the polymeric builder), further non-ionicsurfactants, enzymes, bleaches, bleach activators, bleach catalysts,alkalis, defoamers, and glass protection agents.

In an embodiment, the discrete dosage unit contains no ionic surfactant.

In an embodiment, the continuous gel phase makes up at least 10 wt % ofthe discrete dosage unit (excluding the weight of the containermaterial, if present), preferably at least 15 wt %, preferably at least20 wt %, of the discrete dosage unit. In an embodiment, the discretedosage unit comprises up to 50 wt %, preferably up to 45 wt %, up to 40wt %, up to 35 wt % or up to 30 wt % of the continuous gel phase.

Preferred features of the first and second aspects of the inventionapply mutatis mutandis to the third aspect of the invention.

ADW Use

The fourth and fifth aspects of the invention relate to the applicationof the discrete dosage unit in automatic dishwashing. Preferably, thediscrete dosage unit is used in a dishwasher run that lasts at least 30minutes, preferably at least 35, 40, 45, 50, 55 or 60 minutes. In anembodiment, the discrete dosage unit is released from a dispensercompartment of the dishwasher, during the dishwashing process.

EXAMPLES

The invention is further demonstrated by the following non limitingexamples.

A glass reactor equipped with three inlets, nitrogen inlet and stirrerwas charged with the non-ionic surfactant, optionally a chain transferagent, and optionally a solvent, in the amounts shown in Table 1. It wasrinsed for a few minutes with nitrogen and heated to 75° C. Feeds 1 to 3were connected to the flask and simultaneously added over 4 hours at 75°C. with stirring at 100 revolutions/minute. Feed 1 contained the monomercomponent (acrylic acid), feed 2 contained a polymerization initiatordissolved in a small amount of the non-ionic surfactant and/or solvent,and feed 3 optionally contained a further amount of chain transferagent. After the addition of feeds 1 to 3, the composition was stirredfor an additional hour at 75° C. with stirring at 100revolutions/minute, for post-polymerization. The polymer was poured intoa beaker and immediately cooled to room temperature.

The transparency of the resulting gel was observed visually and noted.It was also observed whether or not the gel was self-standing. Themolecular weight of the polymeric builder was determined by the gelpermeation chromatography method described above. The synthesisvariables and the results are summarised in Table 2.

TABLE 1 Initial charge Feed 1 Feed 2 Feed 3 Weight Weight (g) of Weight(g) Weight (g) Weight (g) of (g) of chain transfer Weight (g) of acrylicWeight (g) of Weight (g) chain transfer Weight (g) Ex. surfactant agentof solvent acid of initiator^(#) surfactant of solvent agent of solvent1 123¹ 45* 95 253 2.40  5⁵ 95 12* 0 2 123¹ 45* 95 253 2.40  5⁵ 95 12* 03 230¹ 0 290 540 5.11 10⁵ 65 10.8** + 29.5*** 19.8 4 230² 0 290 540 5.1110¹ 65 10.8** + 29.5*** 19.8 5 170¹ + 0 320 480 4.54 10⁵ 75  9.6** +26.2*** 44.2  60³ 6 230¹ 0 310 420 3.98 10⁵ 146  8.4** + 22.9*** 48.7¹Surfactant was the reaction product of a C₁₃-C₁₅ alcohol, EO and BO ina molar ratio of 1:9:2 ²Surfactant was the reaction product oftridecanol, EO and PO in a molar ratio of 1:5.5:2 ³Surfactant was thereaction product of a C₆ alcohol and EO in a molar ratio of 1:6(starting from hexylglycol or hexyldiglycol) *Chain transfer agent was(2-ethylhexyl)thioglycolate **Chain transfer agent was 2-mercaptoethanol***Chain transfer agent was NaH₂PO₂ (55% aqueous solution) ^(#)Initiatorwas tertiary-butyl peroxypivalate (purity: 75%) (CAS No. 927-07-01)

TABLE 2 Composition of reaction mixture Total wt % Gel properties TotalWt % chain M_(w) of the Total wt % wt % acrylic transfer polyacrylicSelf- Ex. Surfactant Solvent surfactant solvent acid agent acid (g/mol)Transparent? standing? 1 EO/BO¹ MPG 20 30 43 9 7100 Yes Yes 2 EO/BO¹ DPG20 30 43 9 6000 Yes Yes 3 EO/BO¹ DPG 20 31 45 3 4200 Yes Yes 4 EO/PO²DPG 20 31 45 3 4700 Yes Yes 5 EO/BO¹ + DPG 20 37 40 3 4200 Yes Yes EO³ 6EO/BO¹ DPG 20 42 35 3 4200 Yes No

A range of gels comprising copolymeric builders were synthesized in asimilar manner using a reaction mixture comprising acrylic acid (AA) anditaconic acid (IA) as the monomers, with an AA:IA weight ratio of 70:30or 60:40. The amount of non-ionic surfactant in the reaction mixture was20 wt % in each case. The reaction mixture included either i) 50 wt %DPG, or ii) 40 wt % DPG+10 wt % water, as the solvent(s). The weightaverage molecular weight of the AA/IA builder was varied from 7830 to48500 g/mol. All these gels were transparent.

Identical batches of water-soluble, polyvinyl alcohol injection moulded3-compartment containers were prepared and filled with the followingbase formulations:

TABLE 3 Compartment 1: 9 g of Powder 1: Compartment 2: 1.3 g of Powder2: % % Ingredient by weight Ingredient by weight Trisodium citrate 15TAED 25 Dispersing agent 10 Dispersing agent 22 (Sokalan ™ PA 30 CL(Sokalan ™ PA 30 CL Granules⁴) Granules⁴) Sodium carbonate 30 Sodiumcarbonate 25 Sodium percarbonate 45 Protease 23 Amylase 5 ⁴Polyacrylicacid, sodium salt (Molecular weight 8000 g/mol)

The gels of each of Examples 1-6 were respectively heated to a lowviscosity liquid and optionally combined with a dye to make themcoloured. The third compartment of each batch of the containers was thenfilled with 4 g of one of these respective liquids and allowed to coolto reform the gel phase. On cooling, the transparency is maintained.

In comparative batches of the containers, the third compartment wasfilled instead with 4 g of pure non-ionic surfactant, in each casecorresponding to the surfactant used in the inventive gel.

The containers were each subjected to a dishwashing test according tothe IKW method. Cleaning performance of each of the containerscomprising a gel phase of Examples 1-6 was better than the comparativecontainers, indicating that the polymer in the gel phase is performingas a builder. Furthermore, each of the dosage units dissolved completelyin the wash and left no residues on the dishes.

After storage for 12 weeks at 40° C., 75% relative humidity, thecontainers containing the gel phase of Examples 1-6 were intact withoutany cracks or deformation.

The synthesized AA/IA builder-containing gels were subjected to similartests. All showed builder performance (better cleaning than thecomparative containers in which the gel was substituted for the purenon-ionic surfactant).

The invention claimed is:
 1. A method of manufacturing an automaticdishwashing detergent product being provided as a discrete dosage unitand comprising a continuous, non-aqueous gel phase comprisingmanufacturing the gel phase by a method comprising free radicalpolymerization of one or more monomers in a non-aqueous reaction mixtureto form a polymeric builder without an intermediate step of drying thereaction mixture to form a solid comprising the polymeric builder;wherein the polymeric builder is in a dissolved state in the non-aqueousgel phase, wherein the reaction mixture comprises: 10 wt % to 50 wt % ofa non-ionic surfactant; 10 wt % to 60 wt % of at least one non-watersolvent; and a monomer comprising acrylic acid, wherein no more than 0.1wt % of the total amount of the monomer is a crosslinking monomer. 2.The method according to claim 1, wherein the monomer consists of acrylicacid.
 3. The method according to claim 1, wherein the free radicalpolymerization is conducted at a temperature in the range of 20 to 90°C.
 4. The method according to claim 1, wherein the free radicalpolymerization is conducted at a temperature in the range of 40 to 80°C.
 5. The method according to claim 1, wherein the free radicalpolymerization is conducted in the presence of a chain transfer agent.6. The method according to claim 1, wherein the free radicalpolymerization is conducted in a feed mode of operation, in which atleast a portion of the non-ionic surfactant is present in an initialcharge, and at least a portion of the monomer and at least one radicalinitiator is fed to the initial charge.
 7. The method according to claim1, wherein up to 40 mol % of acid groups in the polymeric builder are inneutralized form.
 8. The method according to claim 1, wherein the gelphase is free of any ionic surfactant.
 9. The method according to claim1, wherein the reaction further comprises a monomer comprisingα,β-ethylenically unsaturated acid; and wherein no more than 0.1 wt % ofthe total amount of the monomers are crosslinking monomers.
 10. Themethod according to claim 9, wherein the non-ionic surfactant comprisesan end-capped alcohol alkoxylate.
 11. The method according to claim 10,wherein the alcohol alkoxylate non-ionic surfactant is liquid at 20° C.12. The method according to claim 9, wherein the reaction mixturecomprises at least 20 wt % in total of the monomers.
 13. The methodaccording to claim 9, wherein the reaction mixture is free ofcrosslinking monomers.
 14. The method according to claim 9, wherein thereaction mixture comprises: at least 20 wt % in total of the non-ionicsurfactant; and at least 40 wt % in total of the monomers.
 15. Themethod according to claim 9, wherein the α,β-ethylenically unsaturatedacid is a carboxylic acid selected from the group consisting ofmethacrylic acid, ethacrylic acid, maleic acid, crotonic acid, itaconicacid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid,and fumaric acid.
 16. The method according to claim 9, wherein theweight ratio of acrylic acid to α,β-ethylenically unsaturated acid inthe reaction mixture is in the range of 100:1 to 1:1.
 17. The methodaccording to claim 1, wherein the non-water solvent is a water-solubleorganic solvent selected from the group consisting of alkylene glycol,dialkylene glycol, monopropylene glycol, and dipropylene glycol.
 18. Themethod according to claim 1, wherein the alcohol alkoxylate non-ionicsurfactant is of the formula R1-O-(EO)x(AO)y-R4, in which: R1 is analkyl group; R4 is H or an optionally substituted alkyl group; x is 1 to100; y is 0 to 100; EO is ethylene oxide; and each AO, when present, isindependently propylene oxide or butylene oxide; wherein x and yrepresent the average degrees of respective alkoxylation per molecule;and wherein the order of EO and AO groups may be varied but the sum of xand y is at least
 3. 19. The method according to claim 1 furthercomprising providing the gel phase in a water-soluble container.
 20. Themethod according to claim 1 further comprising: providing the gel phasein a compartment of a multi-compartment water-soluble container; andproviding a solid composition in a different compartment of themulti-compartment water-soluble container; wherein the solid compositioncomprises a component selected from the group consisting of bleach,enzyme and builder.